Mass

The liturgy of the Eucharist, the central service of the Roman Catholic Church. In the middle ages, the Mass was chanted and was one of the chief sources of music of that period that survive to the present. Many composers throughout European history have set the Mass to music from the early middle ages up through the present time. There are two major categories of the items of the Mass, the Proper, or the texts that are variable, and the Ordinary, or the fixed texts.